Closed system dry cleaning apparatus utilizing volatile solvent



May 26, 1953 w. L. WELLFORD, JR 2,639,599

CLOSED SYSTEM DRY CLEANING APPARATUS UTILIZING VOLATILE SOLVENT Filed Sept. 7, 1949 IN VEN TOR WA/.kE/ A. WELI a/w, JR.

A Horn eys Patented May 26, 1953 (SLGSE'D SYSTEM DRY CLEANING APPARA- TUS UTILIZING VOLATILE SOLVENT Walke L, w l r J M mph s Tom Application September '7, 1849, Serial No. 114,351

(Cl. SSE-=18) 6 filei s- 1 This ir-rventionrelates to, a dryicleaningl process and: apparatus and, moretparticularly, to a closed system utilizing a volatile solvent.

The primaryobject of this invention is-to pro-e. vide a dry cleaning system embodying. one or more of the volatile. solvents which vaporize at or near room temperature. while at atmospheric pressure, but which condenseto; liquid statewhen cooled below the room temperature) or when placed under pressure greater than atmospheric. Generally speaking, it is intended to utilize the superlative cleaning characteristics of these vola-r tile solvents and, further; tozcapitalize; on the sub-. stantially complete removability of the solvents from the work, while achieving; substantially complete recovery or the solvents.

Still another object of theinvention taprovide dry, cleaning, system in which a;- relatively volatile solvent is utilized selectively with or without a liquid soap solution or: a sol-utioncontaining t r disbursin a nts, ut wher in d ri t e r v ry and r cy l -ins f; h ol ent t s. some rated from. th soap. so ution; or disper in ent r n h rei an resi ual: dirt is emoved from bo h. he oa so ution or di ers n a en a d t ntso nv olu ons a dis r ing: aso sar E LVKI Q H L 'h rt and will. e r er ed o e ,inafi er so p solu ons- Yet another obio t. i n oduoosa etv fa tors at he cr t cal p ints-mine r ss was to av xp o ions and out down. he denser Qf leaka e ue t exo ssiv pressu s.

Th e an ther Qhioots I he oor rehiin the fol owin sp oiiioa on and: raw n wh h the o s e iagra matica y re esent th mo ess and apparatus; I

Referring n t he crowns n wh ch ke ence n me a s de ote imi a e men s,- a pr ssu s l n i h the cl aning st is carried out is illustrated alt-2",, it being understood that the vessel is of standard construction exept or he" inl t ndo ot oonnootionsand' also in hat i s suitabl ro nfo o isi nd seamed s s o i h and bo h. intc na an ext rnal ro sures- V s l. is oro dvith a alab e a c s oor or e tin nd. mov nsthe c othes or other work to be dry cleaned, Within vessel 2 there is tumbler 6, also having an access door (not shown), conventionally supported on double stub shaft 8 rotatably mounted on gas-tight bearings it in the ends of pressure vessel 2'. Shaft 8' is rotatably driven by motor 1-2 on other suitable source of motive power.

At the start of the operationworn is'introduced in the tumbler 6, access door 4 i's olosed. andsoaled vessel into receivin tank 2i.

and a volatile. liquid'ispumped through line It to the interior-z of. the, vessel: so that when motor 12 is. operated the work will be agitated and cleaned by transfer 0% dirt or other impurities to they solvent. In addition; asoap solution may be introduced into the, vessel via pipe l4 connected to a suitable source. The invention is concerned primarily withv the remainder of the system.

Leading. from the, bottom of vessel 2 there is shown a drain pipe: 18-. having a manually con-r trolleddrain valve 2on1 its: immediate connection with vessel". During the cleaning operation drain valve 20 is closed, but when the cleaning is finished it is opened so as to permit passage of the soap solution andthe liquid solvent in vessel through drain pipe It and check valve 22 to a liquid receiving tank 25. Tank 24 is at least as large as vessel 2 so that all of the fluids of vessel Zmaybe received.

Branching from drain pipe. It between drain valve 20 and: check valve 22 is line 32 intended primarily for vapors, and including a pump 34 driven by a suitablesource of power (not shown) so as to pump fluids, and especially vapors, from In the description of the operation of this portion of the system it is assumed that the cleaning has been completed with a soap solution and a volatile liquid solvent. Manual "drain valve 20 is opened and most of the solution and most of the solvent will have passed freely through check valve 22 into receiving tank 2& Thereafter, while valves 15 and are closed and drain valve 20 is opened, pump- 34; is operatedso as to draw all possible fluids into receivingtank 22 i. If desired, motor {2 may be continued in operation during this phase of the cycle so as to rotate tumbler 6 and facilitate the disper'sa1 and vaporization of the volatile solvent from the work and centrifugally remove the liquid soap solution or dispersing agent. Once the fluids are drained and pumped into receiving tank; 22 3 they are prevented from returning directly to vessel" 2 by check valves 22 and 35. Check valve 22, of course, also prevents pump 3;? from drawing fluids upwardly through drainpipe I9. lit should be noted that when pump 3 4 is operated, the pressure within vessel 2 is reduced. greatly below that which prevailed during the cleaning of the work. Thus, a solvent selected: from the group; listed below will vaporize readily. because of the reduction in ressure. The amount of pumping down of vessel 2 will dependupon the particular solvent used, and also on the ambienttemperature of the work room in which the system is installed.

Leading from the upper portion of receiving tank 24 is a vapor line 36 also containing the vapor pump 38 and check valve 40 so that when pump 38 is operated by a suitable source of motive power not shown, vapor is withdrawn from the upper portion of receiving tank 24 and pumped to a vapor receiver 42 which is maintained at a reduced temperature by an adjacent refrigerating mechanism diagrammatically illustrated by cooling coil 44. It will be understood that the refrigerating system which includes cooling coil 44 is conventional and that the block illustration will suffice to denote it.

In the operation of this portion of the system, after the fluids in vessel 2 have been drained and pumped into receiving tank 24, drain valve is closed, and valves 50 and 46 described below are also closed. As the pressure in receiving tank 24 is reduced by operation of pump 38 the solvent vaporizes and is withdrawn from receiving tank 24. Upon reaching vapor receiver 42, the solvent may be chilled by pipes 44 and thereby reduced to liquid phase. Even without chilling, pressure in vapor receiver 42 resulting from operation of pump 38 will be sufficient to cause liquification of the vapor therein. Thereafter, the soap solution or dispersing agent is drained out through drain pipe 26 in the bottom of receiving tank 24 by opening drain valve 28. This liquid is returned to a suitable storage vessel from which it can be re-used by introduction back through line l4. Receiving tank 24 contains a conventional scalable cleanout so that all residual dirt or solid matter may be removed.

After the volatile solvent has been returned to storage vessel 42 and chilled, the manually controlled air relief valve 46 may be opened for exhausting air that may have leaked into the system. After the solvent has been chilled, any air that accompanied it into storage vessel 42 will be trapped in the upper part of storage vessel 42 under greater than atmospheric pressure due to the action of pump 38. By carefully opening relief valve 46, the entrapped air may be bled off. The solvent is ready for re-use by opening manual control valve 50 and by operation of pump 52 so as to pass the solvent from storage vessel 42 via line l6 back to work vessel 2.

After work has been cleaned and the fluids withdrawn from vessel 2 there will remain in the work slight traces of the volatile solvent which, if brought into direct and free contact with the atmosphere, might contribute to an explosion. In order to preclude this danger, there is provided a source 54 of inert gas, preferably one of the noble gases such as neon, argon, freon. or xenon which, by opening valve 56, may be passed via tube 58 into receiver 2 so as to intermingle with the volatile gases and thereby inhibit explosion. Thereafter access door may be opened and the work safely removed.

While any one of the number of volatile volvents may be utilized, the following, or mixtures of the following are suitable.

Butane Carbon tetra chloride Propane Freon 11 Pentane Freon 12 Benzene Trichlorethylene Throughout the specification and claims, it will be understood that the definition of a solvent which is vaporous while substantially at room temperature and atmospheric pressure is based or assumed as normal operating temperatures of the workroom ofw adry cleaning plant. The

important characteristics of the solvent are that when the pressure in vessel 2 is reduced by operation of pump 34, that the residual solvent in the work will vaporize and ,be drawn off into the receiving tank 24. If desired, moderate amounts of heat may be applied to facilitate the vaporization and removal of the solvent from the work and vessel 2 and, later on in the process, moderate heat may be applied to the liquid receiving tank 24 to assist in the removal of the solvent from the impurities and the soap solution. In the claims, the term textiles is meant to include the various articles of clothing, household articles such as rugs, linens, and all other fabrics of this general nature which may be dry cleaned. The term dirt is intended to mean all of the foreign substances such as grease, food, dust, earth, paint, and the like which customarily are removed by dry cleaning.

While the processing system detailed above constitutes one embodiment of the invention, it will be understood that various modifications, substitutions may be made without departing from the scope of the following claims.

I claim:

1. A closed dry cleaning system comprising a scalable work vessel, means for agitating work in said work vessel, a scalable receiving vessel, first conduit means connecting said work and receiving vessels whereby to pass said solvent from the work vessel to the receiving vessel, a vapor pump in said first conduit means for pumping vapor from the work vessel to the receiving vessel, valve means in said first conduit means for preventing back flow from said receiving vessel to said work vessel, a closed storage vessel, a second conduit means connecting said receiving and storage vessels, a vapor pump in said second conduit means for pumping vapor from said receiving vessel to said storage vessel, means for transferring solvent through said second conduit means from said storage vessel to said work vessel and valve means in said second conduit means for preventing back flow of liquid from said storage vessel to said'receiving vessel.

2. In the combination claimed in claim 1, means for introducing a liquid detergent into said work vessel, and drain means for draining said detergent from said receiving vessel.

3. A closed dry cleaning system comprising a scalable work vessel, a tumbler in said vessel for agitating work therein, means for driving said tumbler, a scalable receiving vessel below said Work vessel, a drain pipe extending downwardly from said work vessel to said receiving vessel, av

manually operable shut-off valve in said drain pipe, a check valve in said drain pipe below said manually operable valve for preventing passage of fluids upwardly therepast, a vapor conduit conn-ected at one end to said drain pipe between said: valves and connected at its other end to said receiving vessel, a vapor pump in said vapor conduit for pumping vapor from said work vessel via. said drain pipe and manually operable valve into, said receiving vessel, a closed storage vessel, a second vapor conduit connecting the upper portion of said receiving vessel to said storage vessel, a second vapor pump in said second vapor conduit, valve means in said second vapor conduit for preventing back flow of liquid from said storage vessel to said receiving vessel, a supply conduit connecting said storage vessel and said work vessel and manually operable valve means in said supply condu t...

References Cited in the file of this patent UNITED STATES PATENTS Name Date Barbe Nov. 1, 1904 Number Number Number Name Date Aydelotte Febv l, 1927 Mishaw Sept. 16, 1930 Welles Feb. 2, 1932 Lindenberger Dec. 25, 1934 Passar Sept. 1, 1936 Hetzer Dec. 20, 1938 House Jan. 30, 1940 McDonald Apr. 23, 1940 FOREIGN PATENTS Country Date Germany Apr. 22, 1915 

